Essential Oil Diffuser/Humidifier for 80% OFF at Amazon! Ultrasonic diffusers generate the vapor without any heat, which best preserves the integrity of the essential oil. Diffusers are better than any scented candle, you can even combine two or more essential oils to create a unique blend. Diffusers are known to help those who suffer from Dry Cough, Itchy Nose or Eyes, Allergies, Sinus View Post